The Trump administration on Tuesday condemned Boris Johnson's decision to use Huawei's equipment on parts of Britain's fifth-generation mobile phone networks, but it stopped threatening any direct retaliation.
The prime minister tried to defuse the White House's fears of allowing the Chinese telecommunications equipment maker to develop 5G networks, assuring President Donald Trump that Britain would work with the United States to reduce its dependence on Huawei.
Huawei's selection followed a heavy Washington lobby to completely exclude Huawei. A senior Trump administration official called the measure "disappointing", adding, "There is no safe time for unreliable suppliers to control any part of the 5G network."
The United Kingdom's National Security Council approved Huawei, but limited the Chinese company to a 35% market share in the 5G infrastructure and excluded its kit from the sensitive "core" of the networks.
The decision was made despite repeated US warnings that allowing Huawei equipment on the UK's 5G networks would put Britain at risk of spying by the Chinese state.
In a concession to the concerns of the White House, UK ministers agreed to work with partners in the US "Five Eyes" alliance in Australia, Australia, Canada and New Zealand – and other allies – to develop alternative telecommunications providers.
The ultimate goal "there will be no high-risk suppliers in the system," according to British officials informed of the plans, although ministers said it could take three years for new suppliers to enter the market.
In a sign that Washington wants to contain the Huawei line, the Trump administration official said: "We are looking forward to working with the UK on a path that will result in the exclusion of non-trusted vendor components from 5G networks."
Liam Fox, a former UK defense secretary, said he feared in Washington that Britain's decision to stay with Huawei could give a "green light" to other Western allies with less sophisticated security systems to use the company. Chinese.
Johnson, who spoke to Trump on Tuesday, is scheduled to meet with US Secretary of State Mike Pompeo in Downing Street on Thursday.
After the Johnson-Trump call, Downing Street said the prime minister "underlined the importance of countries with similar ideas working together to diversify the market and break the domination of a small number of companies".
UK security officials told the National Security Council that any risk surrounding Huawei could be contained.
Nicky Morgan, secretary of culture, said that world-class connectivity "should not be at the expense of our national security" and the government's goal was to quickly reduce Huawei's role.
"High-risk suppliers have never been and will never be in our most sensitive networks", added Baroness Morgan.
Huawei will be able to supply "non-essential" parts of Britain's 5G networks, as base stations, but not essential elements, such as computer servers.
The 35% market share limit on "high-risk suppliers" will be applied to Huawei's 5G infrastructure kit and its equipment for complete fiber fixed line networks. Currently, the company has a 34% stake, according to authorities.
The National Security Council also stipulated that Huawei – whose role as a high-risk supplier will be declared in new legislation – will be banned from sensitive locations, including nuclear power plants and military bases.
In a statement, the government said its planned measures for a "new rigid telecommunications security structure" would allow the UK to combat a range of threats, "whether cyber criminals or state-sponsored attacks".
Over time, ministers expect companies like Samsung and NEC to enter the UK market, offering additional competition from Huawei and its two main rivals that provide telecommunications kits in Britain: Ericsson and Nokia.
Australia has already bowed to US pressure by banning Huawei from its 5G networks, but Canada and New Zealand have yet to make decisions. It is thought that they can follow Britain's example.
The UK decision could also be influential in some of Huawei's other major European markets, such as Germany, which still has to choose whether to use the Chinese company for 5G networks. Chancellor Angela Merkel took a measured approach, refusing to exclude Huawei, but her position is being criticized by deputies.
Huawei welcomed the UK decision, saying it would keep deploying the 5G infrastructure on track.
"This evidence-based decision will result in a more advanced, more secure and more cost-effective telecommunications infrastructure, suitable for the future"said Victor Zhang, vice president of Huawei. "Give the UK access to the world's leading technology and ensure a competitive market".
The UK's four mobile operators – EE, O2, Three and Vodafone – have launched 5G services in the past six months, all using the Huawei kit.
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